Friday, August 21, 2015

Don’t cringe when you hear the term chelation (key-LAY-shun) therapy. If you have heard about it at all, you may have heard that it is alternative medicine, quackery, expensive, and even dangerous. New research funded by the National Institutes of Health is suggesting that this old treatment has some real life in it and that it may particularly benefit patients with diabetes mellitus and prior heart attacks.

The article goes on with more of the same credulity along with this little tidbit:

There are reasons to think that chelation to remove metals might treat or prevent heart disease.1 Some complications of diabetes mellitus may be caused by chemical reactions that happen to the excess sugar in the blood. These reactions are catalyzed, or facilitated, by metals. The environment is polluted with metals that are toxic to our systems. Lead (gasoline, plumbing), arsenic (well water, rice, apple juice), mercury (many fish), and cadmium (from rechargeable batteries) are among the top 10 most toxic substances listed by the US government. EDTA chelates lead and cadmium.

So now we're adding environmental toxins to the list of risk factors for cardiovascular disease. I've been following this field closely for a long time and this is new to me. Like mercury and autism I guess. It is only the latest in a growing list of purported mechanisms by which chelation might “work.” None of them have strong biologic plausibility. It's interesting to me how the proponents have jumped from one to another over the years.

This is all based, of course, on TACT and its diabetes substudy. For my own take on these two studies see here and here. Suffice it to say for this post that, at least among highly publicized clinical trials, TACT is the most conflicted and flawed study I have been aware of in my career as a physician. (It's too bad the article didn't cite this paper).

The article, though an AHA publication, departs from the AHA's official post-TACT position on chelation, which gives it only a IIb recommendation. And now it appears that TACT 2, a follow up trial, is in the works. I'm not sure what to think about this. I guess that since TACT has changed the status of chelation, in the perception of the medical community, from that of “quackery” to “controversial treatment” another trial may have to be done. But if its funding and conflicts are like those of TACT 1 I am not optimistic.